JPS62128431A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To obtain a light emission characteristic of high directivity without increasing the starting voltage, by forming a bulb of oval cross section and providing an aperture on a shorter side of the oval cross section. CONSTITUTION:Cross section of a glass bulb 10 is formed by a pair of flat surfaces opposing to each other vertically which are connected by two shorter sides of arc bulging toward the outside. Over nearly entire area of one of the arc surfaces is provided an aperture 11. When a fluorescent lamp is lighted, ultraviolet ray generated by the discharge in the glass bulb 10 excites fluorescent material of a fluorescent layer 13 and is converted to visible radiation. While the visible light repeats reflection on a light reflecting layer 12, flat U shape of the cross section reduces the number of repetitions resulting in reduction of the loss in the output light power due to the reflection. Moreover, light is emitted in a concentrated condition within a sharp angle through the light lead-out aperture 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an aperture-type fluorescent lamp having a light emitting aperture, and more particularly to a fluorescent lamp with a highly acute angle of light distribution characteristic.

(Technical Background of the Invention and Problems thereof) In general, aperture-type fluorescent lamps are often used as light sources in copying machines for diazo or electrophotography.

This is because aperture-type fluorescent lamps have an acute light distribution characteristic that concentrates and emits light in a predetermined direction through the aperture shape for light extraction. This type of conventional fluorescent lamp is shown in Figure 6. show.

In this conventional example, a band-shaped aperture shape 2 of a required width is formed almost completely along the direction of the tube 1tch of a straight glass bulge 1.

As shown in the cross-sectional view of FIG. 7, the glass bulb 1 has a substantially circular cross-section, and the inner circumferential surface excluding the aperture 2 is covered with nine strands of fine particles of a material such as alumina or titania. A Q4 film 4 is deposited, and the entire inner peripheral surface of the light-reflecting rA film 4 and the inner surface of the aperture 2 are covered with a fluorescent film 5 made of a fluorescent material.

Therefore, on the inner peripheral surface of the glass bulb 1 where the band-shaped aperture 2 is located, a band-shaped light reflecting film 4 is missing, and a fluorescent film 5 is directly adhered thereto.

The smaller the opening width of the aperture 2, that is, the frontage angle θ, is set, the more the tIi emitted light can be focused in a specific direction, and the more acute the light distribution characteristic can be reduced by 1υ. Such a high-acute angle light distribution characteristic is desired for a light source for copying.

However, when the opening width of the aperture 112 is narrowed, the following problems arise.

′? 1", r, as shown in the graph of Figure 8. If the inner diameter of the sea urchin glass bulb 1 is kept constant and the frontage width W of the aperture 2 is gradually narrowed to narrow the light emission opening, the light reflection membrane 4
Since the reflection loss due to the irradiance increases gradually, the loss of optical output gradually increases. In particular, when the ratio of the opening width W of the aperture 2 to the inner diameter of the glass bulb 1 is set to 0.5 or less,
The optical output was significantly reduced and the loss of optical output was significantly increased.

On the other hand, if the inner diameter of the glass bulb 1 is gradually reduced in accordance with the opening width W of the aperture 2 in order to reduce the loss of optical output, the starting voltage VS of the glass bulb 1 as shown in FIG. There was a problem in that the lighting device had to be large in size as shown in the figure.

[Purpose of the invention]

The present invention was made in consideration of the above circumstances, and the light distribution characteristics at a high angle can be improved to 1! without increasing the starting voltage. The purpose is to provide a fluorescent lamp that can

[Summary of the Invention] The present invention provides a fluorescent lamp in which a reflective film and a fluorescent film are laminated and deposited on the inner surface of the bulb, and the reflective film is cut in a band shape along the tube axis direction to form an aperture. The bulb's cross section is shaped into a flat shape, and the aperture is placed on the short side of this flat shape, which makes it possible to achieve light distribution characteristics at a high angle without increasing the starting voltage. 1 fluorescent lamp with! ? can be done.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5. In the drawings, common parts are given the same reference numerals, and explanations of the overlapping parts will be omitted.

FIG. 2 shows the appearance of an embodiment of the present invention, in which a straight glass bulb 10 is provided with a single aperture 11 for guiding light along almost its entire length along the tube axis direction.

As shown in FIG. 1, the glass bulb 10 has an oval cross section, and has an opening t7 on one of the short sides of the oval.
11 are provided.

As shown in FIG. 1, the cross section of the glass bulb 10 is an ellipse in which both ends of the long parts of vertically opposing flat surfaces are joined together by the short parts of two circular arc surfaces that curve outward. The opening is formed on almost the entire surface of one of the arcuate surfaces.
is set. That is, the inner peripheral surface of the glass bulb 10 excluding the aperture 11 is covered with a light reflecting film 12 made of a light reflecting material such as alumina or titania. The inner peripheral surface of the light reflecting film 12 and the inner surface of the averte layer 11 are entirely coated with a fluorescent film 13 made of a fluorescent material.

Therefore, on the inner circumferential surface of the arcuate surface of the glass bulb 1 where the aperture t-11 is located, the light reflecting film 4 is cut out in the shape of a band in the direction of the tube axis, and the fluorescent film 13 is directly adhered thereto.

Next, the operation of this embodiment will be described.

When the fluorescent lamp is turned on, the ultraviolet rays generated by the discharge inside the glass bulb 10 excites the fluorescent material of the fluorescent film 13 and are converted into visible light.

This visible light is not repeatedly reflected between the light reflecting films 12, but since the cross section of the light reflecting film 12 is curved into a flat U-shape, the repetition of reflection is reduced, and the light output due to reflection is reduced. Losses are reduced. Moreover, light is emitted from the light emitting aperture 11 intensively and at an acute angle. This aperture 1
FIG. 3 shows the light distribution characteristics of the light emitted from -11.

FIG. 3 shows the light distribution characteristics B according to this embodiment as shown in FIGS. 6 and 7.
This is experimental data shown in comparison with the light distribution characteristic A of the conventional example shown in the figure, and the opening width WB of the aperture 11 of the present example shown in FIG. It also shows the light distribution characteristics when the voltage applied during lighting is the same. As is clear from this, the light distribution characteristic B according to this embodiment is more acute at -F4 than that of the conventional example, and the light output is also larger.

That is, according to this embodiment, a light distribution characteristic with a high angle can be obtained with less optical output loss than that of the conventional example. Therefore, the fluorescent lamp of this embodiment is most suitable as a light source for a copying machine which requires a light distribution characteristic with a high acute angle.

Note that the fluorescent lamp of the present invention is not limited to one in which the cross section of the bulb M is oval, but is flat in shape as shown in FIGS. 1
1 may be spaced.

〔Effect of the invention〕

As explained above, the present invention provides a fluorescent lamp in which a reflective film and a fluorescent film are coated on the inner surface of the bulb in a VI layer, and the reflective film is cut out in a band shape along the tube axis direction to form an aperture. The cross section of the L-shaped pallet 1 was formed into a flat shape, and the aperture was arranged on the short side of this flat shape.

Therefore, the present invention reduces the reflection loss due to the light reflection film inside the bulb, reduces the loss of light output, and obtains light distribution characteristics with a high acute angle without increasing the ipH voltage required for lighting. be able to.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an embodiment of the fluorescent lamp according to the present invention, Fig. 2 is an external perspective view of the embodiment shown in Fig. 1, and Fig. 3 is the light distribution characteristic of the embodiment shown in Fig. 1. Figure 4 (A> is a schematic diagram for explaining the Ijf1 mouth width of the conventional example 7 Birch II, and Figure 11 <8) is the 7 Birch V of the embodiment shown in Figure 1.
Figure 5 (Δ), (B
) is a cross-sectional view of a fluorescent lamp according to another embodiment of the present invention, No. 6
The figure is an external perspective view of a conventional fluorescent lamp, FIG. 7 is a cross-sectional view of the conventional example shown in FIG. 6, and FIG. 8 is a decrease in light output when the Ij'd 0 width of the aperture of the conventional example is narrowed down. FIG. 9 is a graph for explaining that when the pipe diameter of a conventional valve is reduced, the starting voltage increases. 1.10...Glass bulb (bulb), 2.11...
・Aperture, 3, 12...Light reflection 1l)l film, 4.1
3... Fluorescent film.

Claims (1)

[Claims] In a fluorescent lamp in which a reflective film and a fluorescent film are laminated and deposited on the inner surface of the bulb, and the reflective film is missing in a band shape along the tube axis direction to form an aperture, the cross section of the bulb is formed into a flat shape. In addition, a fluorescent lamp characterized in that the aperture is arranged on the short side of the flat shape.